The present invention relates to a vascular implant for implanting into a blood vessel of a patient, the vascular implant being transformable from a compressed state into a self-expanded state, comprising a hollow-cylindrical main body with a proximal end and a distal end, a main body lumen and a longitudinal axis, and comprising a portion that has one-piece stent springs successively arranged over the longitudinal axis of the main body, respectively, and circumferentially meandering perpendicularly in relation to the longitudinal axis, respectively, and has an implant material fixed to the stent springs and connecting them, the stent springs only being connected to one another via the implant material and not between one another. The circumferentially meandering stent springs have pointed arches that face alternately toward the proximal end and the distal end of the main body and parallel to the longitudinal axis thereof. The vascular implant also has at least one hollow-cylindrical side body that branches off from the main body and comprises a side body lumen and a side body implant material, the side body lumen being in fluidic connection with the main body lumen.
Such so-called branched vascular implants are known in the prior art. Such vascular implants, which are also referred to as endovascular stents/stent grafts, are implanted for the treatment of aneurysms in arteries. An aneurysm is understood as being a widening or bulging of an arterial blood vessel as a result of congenital or acquired changes of the wall. The bulging may affect the vessel wall as a whole or, as in the case of a so-called false aneurysm or so-called dissection, blood can flow from the lumen of the artery in between the layers of the vessel wall and can tear them apart. Non-treatment of an aneurysm can lead to a rupture of the artery in the advanced stage, with the consequence that the patient internally bleeds.
For the treatment of aneurysms, the vessel concerned is therefore stabilized by implanting a stent/stent graft, in order to avoid rupturing of the vessel.
The stents/stent grafts or vascular implants that are used for the treatment of aneurysms generally consist in this case of a tubular/hollow-cylindrical metal frame, or of individual metal (stent) springs successively arranged, the jacket surface of which is covered with a textile or polymer film, resulting in a hollow-cylindrical body. For implantation, this stent/stent graft is then radially compressed, for example by means of a sheath surrounding and compressing it, so that its cross section is reduced significantly. Then, with the aid of an insertion system, the stent/stent graft is brought into the region of the aneurysm, where the stent is released. Due to the resilience of the metal frame or the metal springs, the stent expands again into its original form, thereby spreading its jacket surface, which becomes clamped internally in the blood vessel proximally and distally with respect to the aneurysm. In this way, the blood can now flow through the stent/stent graft, whereby further loading of the bulging is prevented.
The expansion of the metal frame or the metal elements may in this case be effected, on the one hand, by using self-expanding metal, such as for example nitinol, or else by using a dilation balloon, which is inserted internally into the metal frame, the dilation of which expands the metal frame/the metal elements.
At the location of the vessel at which a stent/stent graft or such a vascular implant is to be inserted, blood vessels often branch off laterally, which is why upon introduction of the vascular implant at such branching locations in the vessel there is the risk of these side vessels being cut off from blood supply by the vascular implant in the main vessel or by the implant material, which can be impermeable to blood. Therefore, in these regions vascular implants often have openings—known as “fenestrations”—in the jacket material or the implant material, in order to direct blood flowing through the vascular implant through these openings and also generally through side branches of the vascular implant, which side branches are separately provided in these openings and are being introduced into the side vessels, also into the side vessels branching off from the vessel. In this way, it is guaranteed that the regions of the body that are supplied by the side vessel are supplied with blood also.
In many cases, the vascular implants or stent/stent grafts to be introduced at such branching regions do not only have fenestrations but also side branches branching off from the main body of the vascular implant, these branches being released in the aneurysmal sac above the branching vessel and serving, for example, as a landing zone for an additional stent graft, which is implanted into the side branch and the branching vessel in order to bridge the aneurysm. In this way it is additionally guaranteed that the side vessels are supplied with blood also.
Critical regions in the human vascular system are, for example, the region of the aorta bifurcation, and also the branching of the Arteriae iliacae communes into the Arteriae iliacae externa and the Arteriae iliacae interna. With each of the branchings, it is usually necessary to ensure the supply to the vessels branching off if the aorta or the Arteriae iliacae have to be treated in this region, for example because of an aneurysm. Presently, in the prior art, for the treatment of abdominal aneurysms stents or stent grafts (together also known as “vascular implants”) are used that consist of a main body with two legs extending distally, which are intended for placement in the Arteriae iliacae communes. Because of its form and placement, such a vascular implant is also referred to as an Y prosthesis.
In the case of many of these implants, the second leg, which is also referred to as the contralateral leg, is inserted separately from the main body, and only after the placement of the main body, in order to facilitate overall placement of the prosthesis. Correspondingly, in the case of this implant, first the main body is deployed by way of a—generally—transfemoral access above the aorta bifurcation. In a second step, a further implant, that is to say the contralateral leg, is then engaged with the main body, thus completing the bifurcation prosthesis.
Vascular implants comprising side branches that are currently known and available in the prior art are usually made either by attaching the side branches d between the stent springs or else by placing the side branches between the pointed arches. A disadvantage of the vascular implants bearing side branches that are known in the prior art is that these vascular implants having side branches usually have an accumulation of material in the region of the branching, such as for example a nitinol ring in the side branch, by means of which the side branch is opened after expansion, or such as for example additionally sewn-in fabric rings of implant material, which in turn necessitate larger insertion systems, and, in narrow vessels, may lead to difficult handling of these vascular implants. The side branches are additionally also very unstable and, as a result, difficult to handle once they have been introduced into the vessel.